Jack Rosenthal’s television play, originally transmitted in the BBC’s Play for Today in 1976, passed into folk legend, at least in the Jewish community. It told the simple but shocking story of young Eliot Green and his apprehensions over his forthcoming Bar Mitzvah and his worry that all the grown men in his life are somewhat immature and imperfect. In the meantime, the family goes through all the stock neuroses of putting on the then almost obligatory celebratory dinner dance.

At the time, it was wonderful to see even such caricatures on mainstream television and Rosenthal’s concept, that the play was about universal themes of adolescence and family rather than insular concerns, was helped by his genial writing and affectionate performances and direction.

So when Don Black offered to put together a Jewish team, including Jule Styne, to stage Bar Mitzvah Boy as a musical, surely it had to be a smash hit? Yet it only ran for 77 performances in London and was equally a failure when reset in 1946 Brooklyn in a New York tryout.

Critics at the time blamed the failure on an awkward mix of American tunes and British words and a focus on the parents’ battles over the Bar Mitzvah party rather than Eliot’s qualms about the whole point of the day. Indeed, Rosenthal himself went on to write 'Smash', a stage play about his own anguish at seeing his television play mangled into a musical West End failure.

So why would a revival of Barmitzvah Boy – the Musical, succeed this time round? Well, the new book by David Thompson (The Scottsboro Boys, and script adaptation for Chicago) goes back to Rosenthal’s original intentions and places Eliot and his worries centre stage so the actions of others are clearly seen through his eyes. Thompson has also reduced cast numbers to an essential 8 from the 14 in the TV play and 12 in the original musical, making for a much tighter focus on the plot, and Don Black has written new lyrics to previously unheard Styne compositions to complement the revisions.

Sue Kelvin and Robert Maskell, as Eliot’s parents Rita and Victor Green, bring out the heart and soul of the aspirational Jewish working class, particularly in the numbers ‘The Bar Mitzvah of Eliot Green’ and ‘We’ve Done Alright. The whole cast is in great voice, but Sue Kelvin's is a marvel - huge, brassy and tender as appropriate. There’s a fine, wonderfully warm performance, beautifully sung, by Lara Stubbs as Lesley, Eliot’s older sister (lucky the new teenager who has one as perceptive and supportive as this!) , who brings everyone together at the end. Will she end up with her current boyfriend, the over-nice Harold (Nicholas Corre) who comes into his own delivering “Harold’s Dilemma'?

Adam Bregman makes his professional debut as Eliot and celebrated his own Bar Mitzvah last year! He is the archetypal 13 year old trying to make sense of the world and those around him and he doesn’t let lyrics or tunes get in the way of conveying what Eliot is trying to tell us. And there's a delicious performance from Hannah Rose-Thompson, as Denise, Eliot's mouthy playground mate, much more than just Rosenthal's clever prism for looking at Eliot's dilemma through non Jewish eyes (and providing a way out of it in the end).

Playing supporting roles in the adult world, Jeremy Rose is pitch perfect as Rabbi Sherman and Hayward B Morse makes Granddad loveable and just a tad irritating as all good Jewish Granddad's should be ...

The big surprise is that only Sue Kelvin and Adam Bregman are actually Jewish. The whole cast invests every performance with a real unforced authenticity

The Gatehouse is configured long and thin but Stewart Nicholls’ musical staging and direction makes good use of the space so that choreography seems both natural and appropriate and never over the top. Edward Court’s four-man band provide richer support than you might expect from a quartet, with an evocative, klezmer vibe to match the music– it’s a pity they were mostly hidden behind a fringed curtain on Grace Smart’s otherwise uncluttered set. Yes the plot is still thin, the music still too American for 1970’s Willesden, but there’s an integrity here that Jack Rosenthal would probably have approved of. Will it be a smash hit? Go and see for yourselves, you’ll have a lovely time deciding.